Remember! Be cautious about copyright, even with open or Creative Commons resources. The resources on these sites generally may be used for personal use, research, teaching, or any Fair Use as defined in Copyright Law. However, any reproduction of these resources on a publicly-available web site may be a violation of copyright law.
There is a giant pool of Creative Commons-licensed content available to you. There are hundreds of millions of works — from songs and videos to scientific and academic material.
How to apply licensing filters and provide attribution:
Flickr: Creative Commons site for photographs and images.
PBS provides free access to streaming media from many of their programs. These are usually categorized by discipline and alre also searchable by title:
PBS Programs list by show:
http://video.pbs.org/programs/
Nova ScienceNow
http://www.pbs.org/wgbh/nova/sciencenow/
For Education/Teachers:
http://www.pbs.org/wgbh/nova/education/video/